So I've searched quite a bit, but couldn't find a post regarding these specific symptoms...

The vehicle makes a rattle noise when the clutch is slightly slipped from stop. Once engaged there's no more rattle noise. I'm pretty sure it's clutch related, possibly a seized t/o bearing. I want to say the noise is a seized bearing and the pressure plate fingers are rubbing on it...that's what it sounds like. If I don't slip the clutch and let it engage by way of engine idle instead of slight gas pedal there's no noise.

Anyone know what this is?

 

Sounds like chatter.

Resurface or replacing the flywheel or clutch will fix that.

Post a YouTube video.

 

the vehicle doesn't feel any different as far as vibrations...

http://www.youtube.com/watch?v=Jg27H...ature=youtu.be

 

That video did not help at all.

Please make a better one and it will be easier to help you.
Maybe take someone with you to film as you drive.

 

Did it just develop? How many miles on the clutch?
Might want to brace yourself for a tranny drop in the near future.

 

I dropped the tranny and found out the springs in the clutch disc were loose.